in conducting the experiment. We are especially thankful for the analytical work performed on the leach solutions by A. C. Leaf, B. Vandercook, and R. Ko of the Hanford Engineering Development Laboratory.

Spent light-water-reactor (LWR) fuel with an average burnup of 28,000 MWd/ MTU was leach-tested at 25°C using a modified version of the International Atomic Energy Agency (IAEA) procedure. Leach rates were determined from tests conducted in five different solutions: deionized water, sodium chloride (NaCl), sodium bicarbonate (NaHC0 3), calcium chloride (CaC1 2) and Waste Isolation Pilot Plant (WIPP) "B" brine solutions. Elemental leach rates are reported based on the release of 90Sr + 90y, 106Ru , 137Cs , 144Ce , 154 Eu , 239+240pu , 244' Cm and total uran i urn. After 467 days of cumulative leaching, the elemental leach rates are highest in deionized water. The elemental leach rates in the different solutions generally decreased from deionized water to the O.03~ NaCl solution to the WIPP "B" brine solution to the 0.03~ NaHC0 3 solution and was a factor of 20 lower in 0.015~ CaC1 2 solution than in deionized water. The leach rates of spent fuel and borosilicate waste-glass were also compared. In sodium bicarbonate solution, the leach rates of the two waste forms were nearly equal, but the glass was increasingly more resistant than spent fuel in calcium chloride solution, followed by sodium chloride solution, WIPP "B" brine solution and deionized water. In deionized water the glass, based on the elemental release of plutonium and curium, was 50 to 400 times more leach resistant than spent fuel.

We would like to thank D. J. Bradley and R. P. Turcotte for contributing to the design of these experiments. R. C. Britton, N. D. Stice and H. Hollis provided assistance in running the tests. A. C. Leaf and F. T. Hara performed the chemical analyses on the large number of samples generated. G. B. Long and S. E. King provided editorial assistance.

Cement waste forms prepared by three processes, casting, cold pressing, and FUETAP (Formed Under Elevated Temperatures and Pressure) have been compared for their leachability by using the MCC-1 leach test. The results indicate that releases of plutonium are not controlled by the waste form matrix and that there is no significant overall advantage to any of the three cement processes from a leachability viewpoint.